14.67. Set Up: The heat energy generated by friction work equals the loss of kinetic energy. The heat that goes into the ice is related to the mass of ice that melts by For ice, The maximum amount of ice melts when the block loses all its kinetic energy and comes to rest. Solve: (a) For and Then gives (b) For and Reflect: Since the ice is at any heat that goes into it causes a phase transition. is 34 mph. When brought to rest from this large initial speed only a very small fraction of the ice melts. Also note the irreversible nature of this; the water won’t refreeze and release energy to get the block moving again. 14.68. Set Up: For aluminum, and Solve: At the cube has volume and density At the volume is V and the density is The mass m of the cube is constant. and Approximate as The density decreases by 14.69. Set Up: Write the volume of the oceans as where d is the average depth and A is the average surface area of the oceans. Assume that only d changes when V changes, so Solve: and
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This note was uploaded on 03/06/2009 for the course PHYS 114 taught by Professor Shoberg during the Spring '07 term at Pittsburg State Uiversity.